Ultrasensitive flow injection chemiluminescence detection of DNA hybridization using nanoCuS tags

A novel and sensitive biosensor for the determination of short sequence of DNA based on flow injection (FI)-chemiluminescence (CL) system of luminol–H2O2–Cu2+ was developed in the present work. The DNA probe labeled with copper sulfide nanoparticles (CuS NPs) could hybridize with target DNA immobilized on glass–carbon electrode (GCE). The hybridization events were monitored by the CL intensity of luminol–H2O2–Cu2+ after the cupric ions was dissolved from the hybrids. A preconcentration process of cupric ions was performed by anodic stripping voltammetry (ASV) technology to improve the sensitivity of the biosensor. Under the optimum conditions, the CL intensity was proportional to the concentration of target DNA in the range of 2.0 × 10−12–1.0 × 10−10 M. A detection limit of 5.5 × 10−13 M of target DNA was achieved. The CL intensity of two-base mismatched sequences and noncomplementary sequences were also detected. The experiments indicated that two-base mismatched sequences showed weaker CL intensity and noncomplementary sequences gave no response at all.